Assignment and handover in a radio communication network

ABSTRACT

A network entity for a radio communication network includes a processing unit which causes a first resource and a second resource for a terrestrial interface of the radio network to be seized, where the first resource is distinct and different from the second resource. The entity includes a network interface through which a handover request or an assignment request message identifying the first and the second resource is sent. A network entity for a radio communication network includes a network interface which receives a handover request message or an assignment request message identifying a first resource and a second resource. The first resource is distinct and different from the second resource. The entity includes a processing unit that selects one of the first and second resources, allocates a radio channel associated with the handover or assignment, selects a bearer for a terrestrial interface and seizes resources for the interface.

TECHNICAL FIELD

The present invention is related to assignment and handover in a radiocommunication network. (As used herein, references to the “presentinvention” or “invention” relate to exemplary embodiments and notnecessarily to every embodiment encompassed by the appended claims.)More specifically, the present invention is related to assignment andhandover in a radio communication network where a first resourceindicator and a second resource indicator are offered together in amessage for selection.

BACKGROUND

This section is intended to introduce the reader to various aspects ofthe art that may be related to various aspects of the present invention.The following discussion is intended to provide information tofacilitate a better understanding of the present invention. Accordingly,it should be understood that statements in the following discussion areto be read in this light, and not as admissions of prior art.

The A-interface is defined in 3GPP as the terrestrial interface betweenthe MSC node and the BSS radio network. Today TDM is the only definedbearer technology for user plane connection defined in the A-interface.The A-interface is defined in 3GPP technical specification 48.001 (3GPPTS 48.001 Base Station System—Mobile-services Switching Centre (BSS—MSC)interface; General aspects) and the references specified therein.

Handover procedures are defined in 3GPP technical specification 23.009(3GPP TS 23.009 Handover Procedures). The technical specificationassumes an A-interface as defined in the 3GPP standard (3GPP TS 48.001Base Station System—Mobile-services Switching Centre (BSS—MSC)interface; General aspects).

FIG. 1 shows the procedure for an intra MSC, inter BSC, GSM to GSMhandover procedure taken from 3GPP TS 23.009 Handover Procedures. Thisprocedure is chosen as an example because it is used below to describethe concept of the new invention.

In regard to problems with existing solutions, currently the effort istaken to enhance the current standardized A-interface and to support theA-interface as well for IP used as bearer for the user plane. Althoughin the further disclosed, reference is made to IP technology as afurther supported technology, the invention is not limited thereto butencompasses any differing bearer technology. It is assumed that during anetwork migration from the currently standardized A-interface (AoTDM) tothe enhanced A-interface (AoIP) the two bearer technologies defined forthe user plane are used in parallel. This may not be needed in allmigration scenarios but it is seen as a likely scenario for manyoperators.

Applying the current 3GPP handover procedure (3GPP TS 23.009 HandoverProcedures) in such a scenario—parallel use of TDM and IP as user planebearer—results in the following issue: When the MSC request channelassignment from the target BSC then the MSC does not know if this BSCcan establish the terrestrial interface using IP as bearer type. The BSChas the final decision on the bearer type because of the followingrules:

-   -   In the BSC the decision for a specific bearer on the terrestrial        interface may depend on the selected speech coder version for        the A-interface.    -   The BSC has always the final decision regarding the radio codec        and the same codec should be used on the terrestrial interface        as on the radio link to avoid additional transcoding.

The MSC has to seize bearer resources for the A-interface user plane(terrestrial interface) before it sends BSSMAP Handover Request messageto the target BSC. If the target BSC cannot support TDM bearer for theterrestrial interface then BSC has to reject the call. MSC could repeatthe BSSMAP Handover Request message using in the new request IP bearerfor the terrestrial interface. This handling would require additionalsignaling on the A-interface and would extend the handover time.

One simple solution to avoid the repetition of the handover requestmessage would be to provide some configuration in MSC about the BSCcapability. However, this solution has the following disadvantages:

-   -   It is static and cannot provide BSC capability for a specific        call    -   It is error-prone due to manual interaction

Another sub-optimal solution would be that the BSC always accepts thebearer type offered from MSC in the handover request. If it cannot usethe codec selected on the radio link on the terrestrial interface, thenBSC should use another offered codec type. This solution has thefollowing disadvantages:

-   -   The operator has to provide transcoder resources in the BSC to        cover the described scenario    -   Inserting a transcoder in the BSC and using compressed speech        codec on the terrestrial interface reduces speech quality and        increases the delay in the speech path

BRIEF SUMMARY OF THE INVENTION

The present invention pertains to a method for using a network entity ofa radio communication network. The method comprises the steps of seizinga first resource and a second resource for a terrestrial interface ofthe network, where the first resource is distinct and different from thesecond resource. There is the step of sending a handover request messageidentifying the first resource and the second resource.

The present invention pertains to a network entity for a radiocommunication network. The entity comprises a processing unit whichcauses a first resource and a second resource for a terrestrialinterface of the radio network to be seized, where the first resource isdistinct and different from the second resource. The entity comprises anetwork interface through which a handover request message identifyingthe first and the second resource is sent.

The present invention pertains to a method for using a network entity ofa radio communication network. The method comprises the steps of seizinga first resource and a second resource for a terrestrial interface ofthe network, where the first resource is distinct and different from thesecond resource. There is the step of sending an assignment requestmessage identifying the first resource and the second resource.

The present invention pertains to a network entity for a radiocommunication network. The entity comprises a processing unit whichcauses a first resource and a second resource for a terrestrialinterface of the radio network to be seized, where the first resource isdistinct and different from the second resource. The entity comprises anetwork interface through which an assignment request messageidentifying the first and the second resource is sent.

The present invention pertains to a network entity for a radiocommunication network. The entity comprises a network interface whichreceives a handover request message identifying a first resource and asecond resource, the first resource distinct and different from thesecond resource. The entity comprises a processing unit that selects oneof the first and second resources, allocates a radio channel associatedwith the handover, selects a bearer for a terrestrial interface andseizes resources for the interface.

The present invention pertains to a method for a network entity of aradio communication network. The method comprises the steps of receivinga handover request message identifying a first resource and a secondresource, the first resource distinct and different from the secondresource. There is the step of selecting one of the first and secondresources. There is the step of allocating a radio channel associatedwith the handover. There is the step of selecting a bearer for aterrestrial interface. There is the step of seizing resources for theinterface.

The present invention pertains to a network entity for a radiocommunication network. The entity comprises a network interface whichreceives an assignment request message identifying a first resource anda second resource, the first resource distinct and different from thesecond resource. The entity comprises a processing unit that selects oneof the first and second resources, allocates a radio channel associatedwith the assignment, selects a bearer for a terrestrial interface andseizes resources for the interface.

The present invention pertains to a method for a network entity of aradio communication network. Any method comprises the steps of receivingan assignment request message identifying a first resource and a secondresource, the first resource distinct and different from the secondresource. There is the step of selecting one of the first and secondresources. There is the step of allocating a radio channel associatedwith the assignment. There is the step of selecting a bearer for aterrestrial interface. There is the step of seizing resources for theinterface.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings, the preferred embodiment of the inventionand preferred methods of practicing the invention are illustrated inwhich:

FIG. 1 shows an intra MSC, inter BSC, GSM to GSM handover procedure.

FIG. 2 shows inter BSC handover using AoTDM and AoIP of the presentinvention.

FIG. 3 shows improved inter BSC HO; BSC selects IP bearer for theterrestrial interface of the present invention.

FIG. 4 shows improved inter BSC HO; BSC selects TDM bearer for theterrestrial interface of the present invention.

FIG. 5 shows the selection of the IP bearer at call setup of the presentinvention.

FIG. 6 shows the selection of the TDM bearer at call setup of thepresent invention.

FIG. 7 is a block diagram of a network entity of the present invention.

DETAILED DESCRIPTION

Referring now to the drawings wherein like reference numerals refer tosimilar or identical parts throughout the several views, and morespecifically to FIGS. 2 and 7 thereof, there is shown a network entity10, such as an MSC, for a radio communication network. The entitycomprises a processing unit 12 which causes a first resource and asecond resource for a terrestrial interface of the radio network to beseized, where the first resource is distinct and different from thesecond resource. The entity comprises a network interface 14 throughwhich a handover request message identifying the first and the secondresource is sent.

Preferably, the network interface 14 receives an acknowledgment of thehandover. The processing unit 12 preferably detects that one of thefirst and second resources is selected for a bearer. Preferably, theprocessing unit 12 causes an unselected one of the first and secondresources to be released.

The network interface 14 preferably sends the handover request messagewith a circuit identifier code of a selected time division multiplexing(TDM) circuit with respect to a TDM bearer, and with a transport addressof a media gateway (MGw) that will terminate an IP connection withrespect to an IP bearer.

The present invention pertains to a method for using a network entity10, such as an MSC, of a radio communication network. The methodcomprises the steps of seizing a first resource and a second resourcefor a terrestrial interface of the network, where the first resource isdistinct and different from the second resource. There is the step ofsending a handover request message identifying the first resource andthe second resource.

Preferably, there is the step of receiving an acknowledgment of thehandover. There is preferably the step of detecting that one of thefirst and second resources is selected for a bearer. Preferably, thereis the step of releasing an unselected one of the first and secondresources.

The sending step preferably includes the step of sending the handoverrequest message with a circuit identifier code of a selected timedivision multiplexing (TDM) circuit with respect to a TDM bearer, andwith a transport address of a media gateway (MGw) that will terminate aninternet protocol (IP) connection with respect to an IP bearer. Thetransport address can include an IP address and a port number.

The present invention pertains to a method for using a network entity10, such as an MSC, of a radio communication network. The methodcomprises the steps of seizing a first resource and a second resourcefor a terrestrial interface of the network, where the first resource isdistinct and different from the second resource. There is the step ofsending an assignment request message identifying the first resource andthe second resource.

Preferably, there is the step of receiving an assignment completemessage that indicates a bearer shall be used on an A-interface userplane connection.

The present invention pertains to a network entity 10 for a radiocommunication network. The entity comprises a processing unit 12 whichcauses a first resource and a second resource for a terrestrialinterface of the radio network to be seized, where the first resource isdistinct and different from the second resource. The entity comprises anetwork interface 14 through which an assignment request messageidentifying the first and the second resource is sent.

The present invention pertains to a network entity 10, such as a BSC,for a radio communication network. The entity comprises a networkinterface 14 which receives a handover request message identifying afirst resource and a second resource, the first resource distinct anddifferent from the second resource. The entity comprises a processingunit 12 that selects one of the first and second resources, allocates aradio channel associated with the handover, selects a bearer for aterrestrial interface and seizes resources for the interface.

Preferably, the network interface 14 sends an acknowledgment of thehandover request. The acknowledgment request preferably includesinformation that identifies which bearer is used on the terrestrialinterface.

Preferably, the handover request message is a BSSMAP handover requestwith a circuit identifier code of a selected time division multiplexing(TDM) circuit with respect to a TDM bearer, and with a transport addressof a media gateway (MGw) that will terminate an IP connection withrespect to an IP bearer.

The present invention pertains to a method for a network entity 10, suchas a BSC, of a radio communication network. The method comprises thesteps of receiving a handover request message identifying a firstresource and a second resource, the first resource distinct anddifferent from the second resource. There is the step of selecting oneof the first and second resources. There is the step of allocating aradio channel associated with the handover. There is the step ofselecting a bearer for a terrestrial interface. There is the step ofseizing resources for the interface.

Preferably, there is the step of sending an acknowledgment of thehandover request. The acknowledgment preferably includes informationthat identifies which bearer is used on the terrestrial interface.

Preferably, the receiving step includes the step of receiving a BSSMAPhandover request with a circuit identifier code of a selected timedivision multiplexing (TDM) circuit with respect to a TDM bearer, andwith a transport address of a media gateway (MGw) that will terminate anIP connection with respect to an IP bearer.

The present invention pertains to a network entity 10, such as a BSC,for a radio communication network. The entity comprises a networkinterface 14 which receives an assignment request message identifying afirst resource and a second resource, the first resource distinct anddifferent from the second resource. The entity comprises a processingunit 12 that selects one of the first and second resources, allocates aradio channel associated with the assignment, selects a bearer for aterrestrial interface and seizes resources for the interface.

The present invention pertains to a method for a network entity 10, suchas a BSC, of a radio communication network. The method comprises thesteps of receiving an assignment request message identifying a firstresource and a second resource, the first resource distinct anddifferent from the second resource. There is the step of selecting oneof the first and second resources. There is the step of allocating aradio channel associated with the assignment. There is the step ofselecting a bearer for a terrestrial interface. There is the step ofseizing resources for the interface.

There is preferably the step of selecting the bearer to be used on anA-interface user plane connection. Preferably, there is the step ofsending an assignment complete message indicating the selected bearer.

Although this invention is explained with reference to 3GPP herein, theinvention is not limited to 3GPP compliant networks but may encompassalso other networks like the (W)iDEN compatible networks.

In the operation of the invention, to improve the inter BSC handoverprocedure for intra MSC or inter MSC handover scenarios, the handovercan be either GSM to GSM handover or WCDMA to GSM handover or any otherHO from any radio technology to GSM such as LTE to GSM.

MSC automatically detects if BSC can support IP on the terrestrialinterface. Therefore, MSC monitors mobile originating and mobileterminating calls. As soon as BSC uses AoIP for any of those calls MSCmarks the BSC as capable to support IP bearer. The call set-up procedurefor AoIP supports that MSC and BSC are negotiating which bearer to use.

MSC seizes resources for the TDM bearer and the IP bearer before thehandover request message is sent to BSC. Then BSC can choose any of thebearer types. In the BSSMAP Handover Request Acknowledge message the BSCinforms the MSC about the selected bearer type. Finally MSC can releasethe seized resources from the not selected bearer type.

FIG. 2 shows the concept of the improved handover procedure. The numbersin the figure indicate the sequence of actions.

In a first step 1, a BSC (source BSC) detects a handover condition andindicates in a second step 2 towards a MSC that a Handover is required.In a next step 3, the MSC seizes TDM resources and resources for otherbearer(s), e.g. IP for the terrestrial interface. Thereafter, in step 4,a handover request is sent towards a further BSC (target BSC) includingan indication about the seized resources. The further BSC (target BSC)selects a bearer for the terrestrial interface and sends anacknowledgement of said handover request in a further step 6 towards theMSC. Either within the acknowledgement or within any other appropriatemessage information which bearer is used on the terrestrial interface isprovided towards the MSC. Finally, the MSC uses the provided informationwhich bearer is used on the terrestrial interface in a step 7 tocontinue handover procedure, e.g. as defined in 3GPP. In addition, theMSC may also use provided information which bearer is used on theterrestrial interface to release the unused but seized resources for theother bearers.

The improvement for the inter BSC handover procedure is based on thefollowing scenario:

-   -   Target BSC can support AoTDM and AoIP        -   Note: the MSC sending the handover request to the target MSC            does not know in advance, which bearer BSC will select.    -   GSM to GSM or WCDMA to GSM handover is performed

MSC monitors the call set-up procedures for mobile originating andmobile terminating calls. Once BSC uses AoIP for any of those calls theMSC marks that BSC is capable using IP on the user plane.

The information whether a BSC supports AoIP may also be provided towardsthe MSC in a different manner, e.g. it might be administered via an O&M(Operations & Maintenance) tool.

During handover procedure, one MSC sends the BSSMAP Handover Request tothe target BSC. This can be either the anchor MSC (intra MSC HOprocedure or sub-sequent inter MSC HO back to anchor MSC), or in thenon-anchor MSC (intra MSC in non-anchor MSC, inter MSC handover orsub-sequent inter MSC handover to another non-anchor MSC).

FIG. 3 shows a possible message flow that can be used for the proposedhandover procedure. In this example the BSC selects IP bearer for theterrestrial interface.

The following steps are shown in FIG. 3:

-   -   First the MSC detects a condition to request channel assignment        from source BSC (step 1). This could be for example the        reception of BSSMAP Handover Required message from BSC (intra        MSC HO) or the reception of MAP Prepare Handover Request message        (inter MSC HO).    -   Then MSC seizes a TDM circuit and IP resources for the        terrestrial interface towards the target BSC. This involves MSC        internal processes and in case of layered network architecture        the MSC-S has to request MGw to seize a TDM termination and an        IP termination (steps 2-5).    -   Then MSC sends the BSSMAP Handover Request message to the target        BSC (step 6). This message includes the circuit identity code        (CIC)—in case MSC allocates the CIC—and a container (AoIP        Container) used to transport IP address information from the MGW        to the BSC.    -   BSC allocates the radio channel, selects the bearer for the        terrestrial interface and seizes resources for this interface        (step 7). Here, the BSC decides to use IP bearer.    -   In the acknowledgment message the BSC provides its user plane        address information within the AoIP Container (step 8). MSC        identifies that IP is selected for the bearer because it        receives the AoIP Container.    -   MSC is passing the contents of the AoIP Container to the MGW        (steps 9, 10).    -   MSC releases the seized TDM resources. In layered architecture        MSC request MGW to release the TDM termination (steps 11, 12).

FIG. 5 shows the selection of the IP bearer at call setup (assignment).

FIG. 4 shows a second example for a possible message flow that can beused for the proposed handover procedure. In this example the BSCselects TDM as bearer for the terrestrial interface.

The steps 1-6 are equal to the case before, where BSC selected IP bearerfor the terrestrial interface. The following steps are different:

-   -   BSC allocates the radio channel, selects the bearer for the        terrestrial interface and seizes resources for this interface        (step 7). In opposite to the previous example, here, the BSC        decides to use TDM bearer.    -   BSC sends the acknowledgement message as defined in 3GPP for        AoTDM (step 8). MSC identifies that TDM is selected for the        bearer because it does not receive the AoIP Container.    -   MSC releases the seized IP resources. In layered architecture        MSC request MGW to release the IP termination (steps 9, 10).

Note, that in case BSC is responsible to allocate the CIC the followingchanges have to be applied to the examples above:

-   -   MSC does not provide a CIC in the Handover Request message (both        examples).    -   If BSC select TDM bearer for the terrestrial interface it        provides a CIC in the Handover Request Acknowledge message        (first example).

FIG. 6 shows the selection of the TDM bearer at call setup (assignment).

Handover (HO) and assignment request are two independent functions.Assignment request is at call setup. It is mandatory to establish theradio connection (mobile terminal to antenna and further to the BSCnode) and to connect that part with the core network.

Handover is a process that is performed during the call when theterminal is moving around. Different handover types can bedistinguished: while moving the terminal may reach the area of a newantenna, a new radio coverage cell, an area that is controlled byanother BSC or even an area that is controlled by another MSC. Furtherintersystem handover is possible, that means a calling subscriber startsa call in the 2G network and changes to the 3G network.

With respect to the invention herein, the relevant handover process isthe inter BSC intra MSC (the BSC is changed, and both BSC nodes arecontrolled by the one MSC).

Not shown (but still possible) is inter BSC inter MSC HO. In this caseBSC and MSC are changed. Not shown but still possible is the intersystem handover where the target system is a GSM system. The sourcesystem can be any technology for example WCDMA or LTE.

With reference to FIGS. 5 and 6, the following are the steps forAssignment.

1. MSC detects a condition to perform call setup.

2. MSC seizes a TDM termination to be used in case BSC selects the TDMbearer for the A-interface user plane connection later. In the ADDRequest MSC specifies the TDM termination identifier to be seized (notshown). The TDM termination identifier can be mapped uniquely to the CICused in this call.

3. MGw replies on the ADD Request.

4. MSC seizes an IP termination to be used in case BSC selects the IPbearer for the A-interface user plane connection later.

5. MGw replies on the ADD Request.

6. MSC sends BSSMAP Assignment Request message to trigger the channelassignment in the target BSC. MSC provides the CIC and the AoIPContainer, where one of them is to be used for the call.

7. BSC establishes the radio channel. Further BSC selects the bearer tobe used on the A-interface user plane connection. In this example (FIG.5) BSC decided to use the TDM bearer.

8. BSC sends Assignment Complete message back to MSC as specified instandard.

9. From the received Assignment Complete message MSC deducts that TDMbearer (see FIG. 6). shall be used on A-interface user plane connection.MSC requests MGw to remove the previously seized IP termination.

10. MGw confirms the SUB Request.

The present invention includes, but is not limited to, the followinginventive steps:

-   -   MSC detects BSS capability to support IP on the terrestrial        interface    -   MSC seizes a TDM and IP bearer before it request channel        assignment from the target BSC    -   MSC releases unused resources after BSC selected a bearer and        informed MSC about the decision

The invention has the following advantages:

-   -   MSC automatically detects if BSC is capable to support IP bearer        for the terrestrial interface    -   The BSSMAP message defined for the 3GPP handover procedure and        assignment procedure can be reused.    -   BSC has full freedom to select the bearer for the terrestrial        interface.    -   No configuration in MSC or BSC is required    -   The procedure is only applicable for the case that AoIP and        AoTDM are used in parallel. The procedure can be removed and        does not have any additional impact in case BSC supports on AoIP        (proposed target solution for future networks).    -   The procedure supports CIC selection in MSC and CIC selection in        BSC (for AoTDM)

ABBREVIATIONS

-   (W)iDEN (Wideband) Integrated Digital Enhanced Network-   3GPP 3^(rd) generation Partnership Project-   AoIP A-Interface (user plane) over IP-   AoTDM A-Interface (user plane) over TDM-   BSC Base Station Controller-   BSS Base Station Subsystem-   BSSMAP Base Station System Management Application Part-   CIC Circuit Identity Code-   GSM Global System for Mobile communications-   HO Handover-   iDEN Integrated Digital Enhanced Network-   IP Internet Protocol-   LTE Long Term Evolution-   MGw Media Gateway-   MSC Mobile Switching Center-   MSC-S Mobile Switching Center Server-   TDM Time-division Multiplexing-   WCDMA Wideband Code Division Multiple Access

Although the invention has been described in detail in the foregoingembodiments for the purpose of illustration, it is to be understood thatsuch detail is solely for that purpose and that variations can be madetherein by those skilled in the art without departing from the scope ofthe invention except as it may be described by the following claims:

The invention claimed is:
 1. A method of operating a Mobile SwitchingCenter (MSC) of a radio communication network, comprising: seizingresources for a Time Division Multiplexed (TDM) bearer and an InternetProtocol (IP) bearer for use on a terrestrial A-interface of the radiocommunication network; sending a handover request message identifyingthe TDM bearer and the IP bearer for use on the terrestrial A-interface,wherein the handover request message includes a circuit identifier code(CIC) of a selected TDM circuit with respect to the TDM bearer and atransport address of a media gateway (MGw) that will terminate an IPconnection with respect to the IP bearer; receiving an acknowledgment ofthe handover; detecting that one of the TDM bearer and the IP bearer isselected; and releasing an unselected one of the TDM bearer and the IPbearer for use on the terrestrial A-interface.
 2. The method of claim 1,wherein seizing the resources is responsive to receiving an indicationthat a handover is required.
 3. A Mobile Switching Center (MSC) for aradio communication network comprising: a processing unit configured tocause resources for a Time Division Multiplexed (TDM) bearer and anInternet Protocol (IP) bearer for use on a terrestrial A-interface ofthe radio communication network to be seized; a network interfaceconfigured to: send a handover request message identifying the TDMbearer and the IP bearer for use on the terrestrial A-interface, whereinthe handover request message includes a circuit identifier code (CIC) ofa selected TDM circuit with respect to the TDM bearer and a transportaddress of a media gateway (MGw) that will terminate an IP connectionwith respect to the IP bearer; and receive an acknowledgement of thehandover; and wherein the processing unit is further configured to:detect that one of the TDM bearer and the IP bearer is selected; andrelease an unselected one of the TDM bearer and the IP bearer for use onthe terrestrial A-interface.
 4. The MSC of claim 3, wherein theprocessing unit is further configured to: cause resources for the TDMbearer and the IP bearer for the terrestrial A-interface of the radiocommunication network to be seized responsive to receiving an indicationthat a handover is required.
 5. A method of operating a Mobile SwitchingCenter (MSC) of a radio communication network, comprising: seizingresources for a Time Division Multiplexed (TDM) bearer and an InternetProtocol (IP) bearer for use on a terrestrial A-interface of the radiocommunication network; and sending an assignment request messageidentifying the TDM bearer and the IP bearer for use on the terrestrialA-interface, wherein the assignment request message includes a circuitidentifier code (CIC) of a selected TDM circuit with respect to the TDMbearer and a transport address of a media gateway (MGw) that willterminate an IP connection with respect to the IP bearer; receiving anassignment complete message that indicates a bearer will be used on theterrestrial A-interface; detecting that one of the TDM bearer and the IPbearer is selected; and releasing an unselected one of the TDM bearerand the IP bearer for use on the terrestrial A-interface.
 6. The methodof claim 5, wherein seizing the resources is responsive to receiving anindication that an assignment is required.
 7. A Mobile Switching Center(MSC) for a radio communication network comprising: a processing unitconfigured to cause resources for a Time Division Multiplexed (TDM)bearer and an Internet Protocol (IP) bearer for use on a terrestrialA-interface of the radio communication network to be seized; and anetwork interface configured to: send an assignment request messageidentifying the TDM bearer and the IP bearer for use on the terrestrialA-interface, wherein the assignment request message includes a circuitidentifier code (CIC) of a selected TDM circuit with respect to the TDMbearer and a transport address of a media gateway (MGw) that willterminate an IP connection with respect to the IP bearer; and receive anassignment complete message that indicates a bearer will be used on theterrestrial A-interface; and wherein the processing unit is furtherconfigured to: detect that one of the TDM bearer and the IP bearer isselected; and release an unselected one of the TDM bearer and the IPbearer for use on the terrestrial A-interface.
 8. The MSC of claim 7,wherein the processing unit is further configured to: cause resourcesfor the TDM bearer and the IP bearer for the terrestrial A-interface ofthe radio communication network to be seized responsive to receiving anindication that an assignment is required.
 9. A Base Station Controller(BSC) for a radio communication network comprising: a network interfaceconfigured to receive a handover request message identifying seizedresources for a Time Division Multiplexed (TDM) bearer and an InternetProtocol (IP) bearer for use on a terrestrial A-interface of the radiocommunication network, wherein the handover request message includes acircuit identifier code (CIC) of a selected TDM circuit with respect tothe TDM bearer and a transport address of a media gateway (MGw) thatwill terminate an IP connection with respect to the IP bearer; aprocessing unit configured to: select one of the TDM bearer and the IPbearer for use on the terrestrial A-interface; and allocate a radiochannel associated with the handover; and wherein the network interfaceis further configured to send an acknowledgment of the handover requestwith information that identifies which bearer is used on the terrestrialA-interface so that an unselected one of the TDM bearer and the IPbearer for use on the terrestrial A-interface is releasable.
 10. Amethod of operating a Base Station Controller (BSC) of a radiocommunication network, comprising: receiving a handover request messageidentifying seized resources for a Time Division Multiplexed (TDM)bearer and an Internet Protocol (IP) bearer for use on a terrestrialA-interface of the radio communication network, wherein the handoverrequest message includes a circuit identifier code (CIC) of a selectedTDM circuit with respect to the TDM bearer and a transport address of amedia gateway (MGw) that will terminate an IP connection with respect tothe IP bearer; selecting one of the TDM bearer and the IP bearer for useon the terrestrial A-interface; allocating a radio channel associatedwith the handover; and sending an acknowledgment of the handover requestwith information identifying which bearer is used on the terrestrialA-interface so that an unselected one of the TDM bearer and the IPbearer for use on the terrestrial A-interface is releasable.
 11. A BaseStation Controller (BSC) for a radio communication network comprising: anetwork interface configured to receive an assignment request messageidentifying resources for a Time Division Multiplexed (TDM) bearer andan Internet Protocol (IP) bearer for use on a terrestrial A-interface ofthe radio communication network, wherein the assignment request messageincludes a circuit identifier code (CIC) of a selected TDM circuit withrespect to the TDM bearer and a transport address of a media gateway(MGw) that will terminate an IP connection with respect to the IPbearer; a processing unit configured to: select one of the TDM bearerand the IP bearer for use on the terrestrial A-interface; and allocate aradio channel associated with the assignment; and wherein the networkinterface is further configured to send an assignment complete messageindicating the selected bearer so that an unselected one of the TDMbearer and the IP bearer for use on the terrestrial A-interface isreleasable.
 12. A method of operating a Base Station Controller (BSC) ofa radio communication network, comprising: receiving an assignmentrequest message identifying seized resources for a Time DivisionMultiplexed (TDM) bearer and an Internet Protocol (IP) bearer of aterrestrial A-interface of the radio communication network, wherein theassignment request message includes a circuit identifier code (CIC) of aselected TDM circuit with respect to the TDM bearer and a transportaddress of a media gateway (MGw) that will terminate an IP connectionwith respect to the IP bearer; selecting one of the TDM bearer and theIP bearer for use on the terrestrial A-interface; allocating a radiochannel associated with the assignment; and sending an assignmentcomplete message indicating the selected bearer so that an unselectedone of the TDM bearer and the IP bearer for use on the terrestrialA-interface is releasable.